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5575: Measurement Systems for Legal Metrology

This 2-hour webinar will introduce measurement system basics, including the use of unit symbols, prefixes, and transitioning within and between measurement systems units. This webinar is ideal for participants who are unfamiliar with performing unit conversion calculations that are frequently required in many legal metrology activities.

Learning Objectives:

At the end of this session, using your notes, NIST SP 811, and NIST HB  44, you will be able to:

  • DEFINE the terms legal unit of measurement and legal metrology.
  • IDENTIFY different systems of measurement units used in U.S. legal metrology.
  • DESCRIBE how the relationships between measurement units are used to form a unit conversion factor.
  • IDENTIFY appropriate unit conversion factors commonly used in legal metrology.
  • RECALL the 5 steps of the unit conversion process.
  • CALCULATE an accurate mathematical unit conversion using dimensional analysis.

Materials & Supplies:

Must have a calculator, smart phone, or spreadsheet that can perform basic calculations.


To refresh familiarity with the math skills needed to successfully perform unit conversion calculations, participants shall submit the completed worksheet with time estimate (minutes) to the instructor by the Wednesday, October 17, 2018 (elizabeth.gentry [at] (elizabeth[dot]gentry[at]nist[dot]gov)). Review how to use your preferred calculator or spreadsheet prior to the webinar. Several supplemental resources are provided. Estimated time to complete: 60 minutes.



Pre-Work Deadline:

Submit the pre-work to the instructor by COB on Wednesday, October 17, 2018.


Participants shall demonstrate accurate unit conversion calculations. This assignment is required to demonstrate successful completion and earn a training certificate. Submit the completed worksheet with time estimate (minutes) to the instructor by Wednesday, November 28, 2018 (e.g., 3 weeks after the webinar elizabeth.gentry [at] (elizabeth[dot]gentry[at]nist[dot]gov)). Estimated time to complete: 60 minutes.

Post-Work Deadline:

Submit the post-work to the instructor by COB on Wednesday, November 28, 2018.

Minimum Requirement(s):

Successful Completion includes completing the pre-work assignment, full attendance and participation in the session activities and discussions, and completing the post-work assignment.


Weights and Measures officials and others who have responsibilities for determining unit conversion calculations between and within measurement systems when conducting legal metrology, regulatory, and enforcement activities. Webinar application activities focus on Weights and Measures examples. This course is available for non-weights and measures participants.


The current fee for webinars is $199. The payment deadline is COB October 29, 2018. Registration fees for State or local weights and measures officials and/or State metrologists are funded by NIST OWM.


Elizabeth Gentry
Phone: 301 - 975 - 3690 
Email: elizabeth.gentry [at] (elizabeth[dot]gentry[at]nist[dot]gov)

Technology Requirement(s):

The webinar will be a live stream, so participants must have a constant connection during the webinar (hard-wired is preferred).

1.  Operating System (browser) configurations:

  • Windows XP (Explorer 8, 9, 10, 11; Mozilla Firefox; Google Chrome)
  • Windows Vista (Internet Explorer or Firefox)
  • Windows 7, 8, or 10 (Mozilla Firefox; Google Chrome; Internet Explorer)
  • Apple Mac OS 10.5x (Mozilla Firefox; Apple Safari; Google Chrome)
  • Ubuntu Linux (Firefox only)

2.  Media players

3.  Optional: If you have never attended an Adobe Connect meeting before:


NIST/Office of Weights and Measures

Created May 31, 2018, Updated July 23, 2020